Hi! This is my first GIMP script (as well as Scheme program), so feedback and style corrections are welcome!
It's a Greeble renderer - greebles are the random protrusions you find on the surface of starships in science fiction. It selects a bunch of random rectangles, then fills them with the foreground and noises them up a bit based on the active brush. It is based on the method described at http://learnfobia.com/category-Computers-47/tutorial-Painting-A-Spaceshi... .